Re: [boost] filesystem::is_directory return true when exception is disabled and this directory does't exist

From: Beman Dawes (bdawes_at_[hidden])
Date: 2004-10-11 10:44:20

At 10:01 AM 10/11/2004, Liao Weijie wrote:
 >// the snip of code in filesystem::is_directory begin---
 >
 >      DWORD attributes = ::GetFileAttributesA(
 >ph.native_directory_string().c_str() );
 >      if ( attributes == 0xFFFFFFFF )
 >        boost::throw_exception( filesystem_error(
 >          "boost::filesystem::is_directory",
 >          ph, fs::detail::system_error_code() ) );
 >      return (attributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
 >
 >//-------------------------------------------------------end--
 >
 >When GetFileAttributesA failed but the exception is disabled,  the
 >(attributes & FILE_ATTRIBUTE_DIRECTORY)  will always be true.
 >
 >Is it a bug?

No. It is undefined behavior for boost::throw_exception() to return.

To quote the throw_exception() docs:

      Callers of throw_exception are allowed to assume that the
      function never returns; therefore, if the user-defined
      throw_exception returns, the behavior is undefined.

--Beman